ELECTRONICS INDUSTRIES Rework of Electronic · PDF fileIPC-7711 - Includes Change 1 Rework of...

IPC-7711 - Includes Change 1

Rework of Electronic

Assemblies

Developed by the Electronic Assembly Rework Task Group (7-34b)of IPC

Users of this standard are encouraged to participate in the

development of future revisions.

Contact:

IPC2215 Sanders RoadNorthbrook, Illinois60062-6135Tel 847 509.9700Fax 847 509.9798

IPC-7711, Chg 1 - May 2002IPC-7711 - February 1998Supersedes:IPC-R-700C - January 1988

ASSOCIATION CONNECTINGELECTRONICS INDUSTRIES ®

AcknowledgmentAny Standard involving a complex technology draws material from a vast number of sources. While the principal members of theIPC Electronic Assembly Rework Task Group (7-34b) of the Product Assurance Committee are shown below, it is not possible toinclude all of those who assisted in the evolution of this standard. To each of them, the members of the IPC extend their gratitude.

Product AssuranceCommittee

Electronic Assembly ReworkTask Group

Technical Liaison of theIPC Board of Directors

ChairmanMel ParrishSoldering Technology International

ChairmanDaniel L. FosterSoldering Technology International

Vice ChairmanPeggi BlakleyNSWC Crane

William Beckenbaugh, Ph.D.Sanmina-SCI Corporation

A Special Note of Appreciation

The following core group hasvolunteered much of their time andhave made significant contributionsto this document.

Blakley, Peggi, NSWC CraneBrock, Ron, NSWC Crane

Day, Jennifer, Current Circuits

Ferry, Jeff, Circuit TechnologyCenter, Inc.

Foster, Daniel L., Soldering TechnologyInternational

Hersey, Ralph J., Ralph Hersey& Associates

Houghton, F.D. Bruce, CelesticaCorporation

Moffitt, James H., Moffitt ConsultingServices

Norton, John S., Tektronix Inc.

Siegel, Eric, PACE, Inc.

Electronic Assembly Rework Task Group

Aoki, Masamitsu, Toshiba ChemicalCorp.

Ashaolu, Peter, Cisco Systems Inc.Bates, Timothy E., Alcatel USABergum, Erik J., Polyclad LaminatesBlakley, Peggi, NSWC CraneBoerdner, Richard W., EJE ResearchBogert, G.L., Bechtel Plant Machinery,

Inc.Bradford, Diana, Soldering Technology

InternationalBrock, Ron, NSWC CraneCash, Alan S., Northrop Grumman

CorporationChen, D. Phillip, Honeywell CanadaCirimele, Ray, BEST Inc.D’Andrade, Derek, Surface Mount

Technology CentreDaugherty, Dale, Siemens Energy &

AutomationDay, Jennifer, Current CircuitsDeane, William, EPTAC CorporationDehne, Rodney, O.E.M. WorldwideDennehy, Charles S., Circuit

Technology Center Inc.Dieffenbacher, William C., BAE

Systems Controls

DiFranza, Michele J., The Mitre Corp.Dutcher, Nancy, U.S. Assemblies

Hallstead Inc.Etheridge, Thomas R., Boeing Aircraft

& MissilesFalconbury, Gary, Raytheon Technical

Services Co.Ferry, Jeff, Circuit Repair CorporationFieselman, Charles D., Solectron

Technology Inc.Foster, Daniel L., Soldering Technology

InternationalFreeman, Fortunata A., Solectron

Technology Inc.Gillespie, Alan L., Boeing Aircraft &

MissilesGonzalez, Constantino, ACME, Inc.Griffiths, William F., Plessey Tellumat

South AfricaGrim, Edward A., Raytheon Systems

CompanyHargreaves, Larry, DC. Scientific Inc.Herrberg, Steven A., Hughes Defense

CommunicationsHiett, Carol E., Lockheed Martin

AstronauticsHill, Michael E., Dynamic Details Inc.

Ho, David P., Circuit Graphics Ltd.Houghton, F. D. Bruce, CelesticaHymes, Les, Les Hymes AssociatesJohnson, Kathryn L., Hexacon Electric

CompanyJohnson, Laurence G., General Electric

Co.Jones, Sue A., Compaq Computer

CorporationKemp, Cindy A., Evenflo Company

Inc.Kennady, Richard, Bahiatech Bahia

Technologia Ltda.Kern, Terence, Axiom Electronics, Inc.Konsowitz, Robert J., Glasteel

Industrial LaminatesKorth, Connie M., Reptron

Manufacturing Services/HibbingLambert, Leo P., EPTAC CorporationLee, Frederic W., Northrop Grumman

Norden SystemsMacLennan, Karen E., M/A-COM Inc.Maher, Peter E., PEM ConsultingMalewicz, Wesley R., Siemens Medical

Systems Inc.Mastorides, John, Sypris Electronics,

LLC

A special note of thanks is due to PACE, Metcal and Circuit Technology Centerfor the preparation of the illustrations in this document.

May 2002 IPC-7711

iii

May, William Dean, NSWC - CraneMcCormick, Becky, EMD Associates

Inc.Meeks, Jr., Stephen, White Electronic

Designs Corp.Miller, Christine A., FORE SystemsMoffitt, James H., Moffitt Consulting

ServicesMoir, Jim, Hewlett Packard Co.Neumark, Yori, Hadco Corp.Nicol, DavidNortham, Riley L., EMPF/ACINorton, John S., Tektronix Inc.Nunnelley, Benetta, IEC Electronics

Corp.Nuppola, Seppo, Nokia Networks,

Switching PlatformParrish, Mel, Soldering Technology

International

Poelking, Monica, Defense SupplyCenter Columbus

Quinn, Paul J., Lockheed MartinMissiles & Space

Raby, Jim D., Soldering TechnologyInternational

Rassal, David, 3COM CorporationRausch, James E., Delphi Delco

Electronics SystemsRaye, John F., Defense Supply Center

ColumbusRobertson, David E.Rowe, Teresa M., AAI CorporationSanford, Kelly, Micron Custom Mfg.

Services Inc.Scott, Patricia A., Soldering

Technology InternationalSherman, Lowell, Defense Supply

Center Columbus DSCC

Siegel, Eric, PACE, Inc.Smith, Rick B., Motorola Inc.Sober, Douglas J., Essex Technologies

Group, Inc.Steele, David B., Lucent Technologies

Inc.Steen, Wayne A., Rockwell CollinsTevels, John R., Harris Corp.Thompson, Ronald E., NSWC - CraneTorres, Steven, Corlund Electronics

Corp.Ventress, Sharon T., U.S. Aviation &

Missile CommandWoodford, James Walter, Department

of DefenseWooldridge, James R., Rockwell

InternationalXiao, Nora, Tektronix Inc.Youngblood, Don, Honeywell Inc.

Foreword

IPC’s documentation strategy is to provide distinct documents that focus on specific aspects of electronic packaging issues.In this regard document sets are used to provide the total information related to a particular electronic packaging topic. Adocument set is identified by a four digit number that ends in zero (0) (i.e., IPC-7710).

This standard is intended to provide information on the rework, repair and modification of printed boards and electronicassemblies. This information must also be supplemented by a performance specification that contains the requirements forthe chosen technology. When used together, these documents should lead both manufacturer and customer to consistentterms of acceptability.

These documents supersede the following:

IPC-7711 supersedes IPC-R-700CIPC-7721 supersedes IPC-R-700C

As technology changes, a performance specification will be updated, or new focus specifications will be added to the docu-ment set. The IPC invites input on the effectiveness of the documentation and encourages user response through completionof ‘‘Suggestions for Improvement’’ forms at the end of each document.

IPC-7711 May 2002

iv

Table of Contents

1 General ............................................................................................................................................................................................... 1

2 Handling/Cleaning

Procedure Description Product Class Skill LevelLevel of

Conformance

2.1A Handling Electronic Assemblies R,F,W,C Intermediate High

2.2 Cleaning R,F,W,C Intermediate High

2.3 Conditioning


Conformance

2.3.1 Baking and Preheating R,F,W,C Intermediate High

2.4 Coating


Conformance

2.4.1 Removal, Identification of Conformal Coating R,F,W,C Advanced High

2.4.2 Removal, Solvent Method R,F,W,C Advanced High

2.4.3 Removal, Peeling Method R,F,W,C Advanced High

2.4.4 Removal, Thermal Method R,F,W,C Advanced High

2.4.5 Removal, Grinding/Scraping Method R,F,W,C Advanced High

2.4.6 Removal, Micro Blasting Method R,F,W,C Advanced High

3 Removal

3.1 Through-Hole Removal

Procedure DescriptionRound Lead

Product Class Skill LevelLevel of

Conformance

3.1.1A Continuous Vacuum Method R,F,W Intermediate High

3.1.2 Continuous Vacuum Method - Partial Clinch R,F,W Intermediate High

3.1.3 Continuous Vacuum Method - Full Clinch R,F,W Intermediate High

3.1.4 Full Clinch Straigthening Method R,F,W Intermediate High

3.1.5 Full Clinch Wicking Method R,F,W Advanced High

May 2002 IPC-7711

v

4 Pad/Land Preparation


Conformance

4.1.1 Surface Mount Land Preparation - Individual Method R,F,W,C Intermediate High

4.1.2 Surface Mount Land Preparation - Continuous Method R,F,W,C Intermediate High

4.1.3 Surface Solder Removal - Braid Method R,F,W,C Intermediate

4.2.1 Pad Releveling R,F,W,C Intermediate Medium

4.3.1 SMT Land Tinning R,F,W,C Intermediate Medium

4.4.1 Cleaning SMT Lands R,F,W,C Intermediate High

5 Installation

5.1 Through-Hole Installation

Procedure Description

Install following the requirements of J-STD-001 andJ-HDBK-001

5.2 PGA and Connector Installation


Conformance

5.2.1 Solder Fountain Method with PTH Prefilled R,F,W,C Expert Medium

5.3 Chip Installation


Conformance

5.3.1 Solder Paste Method R,F,W,C Intermediate High

5.3.2 Point to Point Method R,F,W,C Intermediate High

5.4 Leadless Component Installation (To Be Developed)

5.5 Gull Wing Installation


Conformance

5.5.1A Multi-Lead Method - Top of Lead R,F,W,C Advanced High

5.5.2 Multi-Lead Method - Toe Tip R,F,W,C Advanced High

5.5.3 Point-to-Point Method R,F,W,C Intermediate High

5.5.4 Hot Air Pencil/Solder Paste Method R,F,W,C Advanced High

5.5.5 Hook Tip w/Wire Layover (To be developed) R,F,W,C Intermediate High

5.5.6 Blade Tip with Wire R,F,W,C Advanced High

IPC-7711 May 2002

viii

5.6 J-Lead Installation


Conformance

5.6.1 Wire Solder Method R,F,W,C Advanced High

5.6.2 Point-to-Point Method R,F,W,C Intermediate High

5.6.3 Solder Paste Method/Hot Air Pencil R,F,W,C Advanced High

5.6.4 Multi-Lead Method R,F,W,C Intermediate High

5.7 BGA/CSP Installation


Conformance

5.7.1 Using Wire Solder to Prefill Lands R,F,W,C Advanced High

5.7.2 Using Solder Paste to Prefill Lands R,F,W,C Advanced High

5.7.3 BGA Reballing Procedure R,C Advanced High

6 Removing Shorts


Conformance

6.1.1 J-Leads - Draw Off Method R,F,W,C Intermediate High

6.1.2 J-Leads - Respread Method R,F,W,C Intermediate High

6.1.3 Gull-Wing - Draw Off Method R,F,W,C Intermediate High

6.1.4 Gull-Wing - Respread Method R,F,W,C Intermediate High

7 Bonding/Coating


Conformance

7.1.1 Epoxy Mixing and Handling R,F,W,C Intermediate High

7.2.1 Replacement, Solder Resist R,F,W,C Intermediate High

7.3.1 Replacement, Conformal Coatings/Encapsulants R,F,W,C Intermediate High

8 Wires

8.1 Splicing


Conformance

8.1.1 Mesh Splice N/A Intermediate Low

8.1.2 Wrap Splice N/A Intermediate Low

8.1.3 Hook Splice N/A Intermediate Low

8.1.4 Lap Splice N/A Intermediate Low

May 2002 IPC-7711

ix

Rework of Electronic Assemblies

1.0 General

1.1 Scope This document covers procedures for repair-ing and reworking printed board assemblies. It is an aggre-gate of information collected, integrated and assembled bythe Repairability Subcommittee (7-34) of the ProductAssurance Committee of the IPC.

1.2 Purpose This document prescribes the proceduralrequirements, tools and materials and methods to be usedin the modification, rework, repair, overhaul or restorationof electronic products. Although this document is based inlarge part on the Product Class Definitions of ANSI/J-STD-001, this document should be considered applicable to anytype of electronic equipment. When invoked by contract asthe controlling document for the modification, rework,repair, overhaul or restoration of products, the requirementsflowdown apply.

IPC has identified the most common equipment and pro-cess in order to affect a specific repair or rework. It is pos-sible that alternate equipment and processes can be used tomake the same repair. If alternate equipment is used, it isup to the user to determine that the resultant assembly isgood and undamaged.

1.2.1 Definition of Requirements The wordsmust andshall have no special meaning beyond that commonly usedin other IPC standards.

1.2.2 Requirements Flowdown The applicable require-ments of this document must be imposed by each manufac-turer or supplier on all applicable subcontracts and pur-chase orders. The manufacturer or supplier must notimpose or allow any variation from these requirements onsubcontracts or purchase orders other than those that havebeen approved by the user. Unless otherwise specified, therequirements of this document are not imposed on the pro-curement of off the shelf assemblies or subassemblies.However, the manufacturer of these items may comply asdeemed appropriate.

1.3 Background Today’s PC boards are more complexand microminiaturized than ever before. Despite this, theycan be successfully modified, reworked or repaired if theproper techniques are followed. This manual is designed tohelp you repair, rework and modify PC boards reliably. Theprocedures in this document have been obtained from endproduct assemblers, printed board manufacturers and endproduct users who recognized the need for documentingcommonly used rework, repair and modification tech-niques. These techniques have, in general, been proven to

be acceptable for the class of product indicated throughtesting and extended field functionality. Procedures con-tained herein were submitted for inclusion by commercialand military organizations too numerous to list individu-ally. The Repairability Subcommittee has, where appropri-ate, revised procedures to reflect improvements.

Rework completed satisfactorily will meet the originalspecification and requirements of IPC-A-600 and IPC-A-610. But, by definition, modifications and repairs do notcomply with the initial design or fabrication criteria. Formodification and repair, the user must recognize that thecriteria in IPC-A-600 Acceptability of Printed Boards andIPC-A-610 Acceptability of Printed Board Assemblies arenot necessarily applicable to the procedures herein. Modi-fications and repairs should not compensate for the lack ofproper processes and quality controls. Ultimate cost effec-tiveness is achieved using appropriate design, fabricationand assembly techniques that minimize the need for modi-fication and repair.

1.4 Controls Although modification, rework and repairprocedures may be very similar, the control of such proce-dures may not be the same, due to the conditions andobjectives involved.

1. ModificationThe revision of the functional capability of a productin order to satisfy new acceptance criteria.

Modifications are usually required to incorporatedesign changes which can be controlled by drawings,change orders, etc. Modifications should only be per-formed when specifically authorized and described indetail on controlled documentation.

2. ReworkThe act of reprocessing non-complying articles,through the use of original or equivalent processing, ina manner that assures full compliance of the articlewith applicable drawings or specifications.

3. RepairThe act of restoring the functional capability of adefective article in a manner that precludes complianceof the article with applicable drawings or specifica-tions.

Repairs are generally changes to an unacceptable endproduct to make it acceptable in accordance with origi-nal functional requirements. The control of repairedproducts should be by means of Material ReviewBoard (MRB), or its equivalent, which may consist of

May 2002 IPC-7711

1

1.9.9 The rework of circuit boards assembled using leadfree solders are similar to common alloys except as notedbelow. Proper training needs to be in place to ensure qual-ity and reliability of the assembly. Generally all that isneeded is to understand those differences.

Those differences are:

• In most cases the newer alloys will require more time andtemperature and one must understand why

• The melting point of the solder alloys are likely to behigher and thus may require a modified flux chemistry

• Wetting times are generally extended

• Solderability indicators such as wetting angles, jointappearance etc., will generally be different

• Higher temperatures and longer dwell times may increaseoxidation

• Component lead frames as well as circuit board finishesmust be compatible with the solder alloy

• Using alternative means of attachment for rework/repair(such as conductive epoxies) may be advantages due totemperature and other considerations

• For both conductive and convective assembly rework/repair, the use of inert atmosphere (such as nitrogen)should be considered to facilitate the process

May 2002 IPC-7711

9

OUTLINE

Electrostatic Discharge (ESD) is the rapid discharge of electri-cal energy that was created from static sources. When theelectrical energy is allowed to come in contact with or evenclose to a sensitive component it can cause damage to thecomponent. Electrostatic-Discharge Sensitive (ESDS) compo-nents are those components that are affected by these highenergy surges. The relative sensitivity of a component to ESDis dependent upon its construction and materials. As compo-nents become smaller and operate faster, the sensitivityincreases.

Electrical Overstress (EOS) is the internal result of a unwantedapplication of electrical energy that results in damaged com-ponents This damage can be from many different sources,such as electrically powered process equipment or ESDoccurring during handling or processing.

ESDS components can fail to operate or change in value as aresult of improper handling or processing. These failures canbe immediate or latent. The result of immediate failure can beadditional testing and rework or scrap. However the conse-quences of latent failure are the most serious. Even thoughthe product may have passed inspection and functional test,it may fail after it has been delivered to the customer.

It’s important to build protection for ESDS components intocircuit designs and packaging. However, in the manufacturingand assembly areas, we often work with unprotected elec-tronic assemblies that are attached to the ESDS components.This section will be dedicated to safe handling of these unpro-tected electronic assemblies.

For that purpose, the following subjects are addressed:

2.1.1 Electrical Overstress (EOS) Damage Prevention2.1.2 Electrostatic Discharge (ESD) Damage Prevention2.1.3 Physical Handling

Information in this specification is intended to be general innature. Additional detailed information can be found in EIA-625, Requirements for Handling Electrostatic-Discharge-Sensitive (ESDS) Devices

2.1.1 Electrical Overstress (EOS) Damage Prevention

Electrical components can be damaged by unwanted electri-cal energy from many different sources. This unwanted elec-

trical energy can be the result of ESD potentials or the resultof electrical spikes caused by the tools we work with, such assoldering irons, soldering extractors, testing instruments orother electrically operated process equipment. Some devicesare more sensitive than others. The degree of sensitivity is afunction of the design of the device. Generally speaking higherspeed and smaller devices are more susceptible than theirslower, larger predecessors. The purpose or family of thedevice also plays an important part in component sensitivity.This is because the design of the component can allow it toreact to smaller electrical sources or wider frequency ranges.With todays products in mind, we can see that EOS is a moreserious problem than it was even a few years ago. It will beeven more critical in the future.

When considering the susceptibility of the product we mustkeep in mind the susceptibility of the most sensitive compo-nent in the assembly. Applied unwanted electrical energy canbe processed or conducted just as an applied signal would beduring circuit performance.

Before handling or processing sensitive components, toolsand equipment need to be carefully tested to ensure that theydo not generate damaging energy, including spike voltages.Current research indicates that voltages and spikes less than0.5 volt are acceptable. However, an increasing number ofextremely sensitive components require that soldering irons,solder extractors, test instruments and other equipment mustnever generate spikes greater than 0.3 volt.

As required by most ESD specifications including EIA-625,periodic testing may be warranted to preclude damage asequipment performance may degrade with use over time.Maintenance programs are also necessary for process equip-ment to ensure the continued ability to not cause EOS dam-age.

EOS damage is certainly similar in nature to ESD damage,since damage is the result of undesirable electrical energy.

2.1.2 Electrostatic Discharge (ESD) Damage Prevention

The best ESD damage prevention is a combination of prevent-ing static charges and eliminating static charges if they dooccur. All ESD protection techniques and products addressone or both of the two issues.

Product Class: R, F, C, W

Skill Level: Intermediate

Level of Conformance: High

7711

Rework of

Electronic Assemblies

Revision: A

Date: 5/02

Handling ElectronicAssemblies

Number: 2.1

Material in this manual, IPC-7711 Rework of Electronic Assemblies, was voluntarily established by Technical Committees ofIPC. This material is advisory only and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to theuse, application, or adaptation of this material. Users are also wholly responsible for protecting themselves against all claimsor liabilities for patent infringement. Equipment referenced is for the convenience of the user and does not imply endorsementby IPC.

Page 1 of 4

ESD damage is the result of electrical energy that was gener-ated from static sources either being applied or in close prox-imity to ESDS devices. Static sources are all around us. Thedegree of static generated is relative to the characteristics ofthe source. To generate energy relative motion is required.This could be contacting, separation, or rubbing of the mate-rial.

Most of the serious offenders are insulators since they con-centrate energy where it was generated or applied rather thanallowing it to spread across the surface of the material. Com-mon materials such as plastic bags or Styrofoam containersare serious static generators and as such are not to beallowed in processing areas especially static safe areas. Peel-ing adhesive tape from a roll can generate 20,000 volts. Evencompressed air nozzles which move air over insulating sur-faces generate charges.

Destructive static charges are often induced on nearby con-ductors, such as human skin, and discharged into conduc-tors. This can happen when a printed board assembly is

touched by a person having a static charge potential. Theelectronic assembly can be damaged as the dischargepasses through the conductive pattern to a static sensitivecomponent. Static discharges may be too low to be felt byhumans (less than 3500 volts), and still damage ESDScomponents. Typical static voltage generation is included inTable 2.

2.1.3 Physical Handling

Care must be taken during acceptability inspections to ensureproduct integrity at all times. Table 3 provides general guid-ance.

Physical Damage

Improper handling can readily damage components andassemblies (e.g., cracked, chipped or broken componentsand connectors, bent or broken terminals, badly scratchedboard surfaces and conductor lands). Physical damage of thistype can ruin the entire assembly or attached components.

Contamination

Contamination by handling with bare hands or fingers withoutsome form of protection causes soldering and coating prob-lems; body salts and oils, and unauthorized hand creams aretypical contaminants. Body oils and acids reduce solderability,promote corrosion and dendritic growth. They can also causepoor adhesion of subsequent coatings or encapsulates.Lotion formulated specifically for use in solder assembly areasis available. Normal cleaning procedures will not alwaysremove such contaminants. The best solution is to preventcontamination.

Table 1 Typical Static Charge Sources

Work surfaces Waxed, painted or varnished surfacesUntreated vinyl and plasticsGlass

Floors Sealed concreteWaxed or finished woodFloor tile and carpeting

Clothes andpersonnel

Non-ESD smocksSynthetic materialsNon-ESD ShoesHair

Chairs Finished woodVinylFiberglassNon-conductive wheels

Packaging andhandling materials

Plastic bags, wraps, envelopesBubble wrap, foamStyrofoamNon-ESD totes, trays, boxes, partsbins

Assembly tools andmaterials

Pressure spraysCompressed airSynthetic brushesHeat guns, blowersCopiers, printers

Table 2 Typical Static Voltage Generation

Source 10-20% humidity 65-90% humidity

Walking on carpet 35,000 volts 1,500 volts

Walking on vinylflooring

12,000 volts 250 volts

Worker at a bench 6,000 volts 100 volts

Vinyl envelopes(Work Instructions)

7,000 volts 600 volts

Plastic bag pickedup from the bench

20,000 volts 1,200 volts

Work chair withfoam pad

18,000 volts 1,500 volts

IPC-7711

Number: 2.1

Revision: A

Date: 5/02

Subject: Handling Electronic Assemblies

Page 2 of 4

Handling Electronic Assemblies

If no ESDS markings are on an assembly, it still needs to behandled as if it were an ESDS assembly. However, ESDScomponents and electronic assemblies need to be identifiedby suitable EOS/ESD labels. Many sensitive assemblies willalso be marked on the assembly itself, usually on an edgeconnector. To prevent ESD and EOS damage to sensitivecomponents, all handling, unpacking, assembly and testingmust be performed at a static controlled work station.

Avoid contaminating solderable surfaces prior to soldering.Whatever comes in contact with these surfaces must beclean. When boards are removed from their protective wrap-pings, handle them with great care. Touch only the edgesaway from any edge connector tabs. Where a firm grip on theboard is required due to any mechanical assembly procedure,gloves meeting EOS/ESD requirements need to be worn.These principles are especially critical when no-clean pro-cesses are employed.

Handling After Solder

After soldering and cleaning operations, the handling of elec-tronic assemblies still requires great care. Finger prints areextremely hard to remove and will often show up in confor-mally coated boards after humidity or environmental testing.Gloves or other protective handling devices need to be usedto prevent such contamination. Use mechanical racking orbaskets with full ESD protection when handling during clean-ing operations.

Common Tools and Equipment

Work environments require tools and equipment to conductelectronic assembly operations. The following information isprovided as guidance regarding the use of common equip-ment. EIA-625 provides more specific information.

Table 3 General Rules forHandling Electronic Assemblies

1. Keep work stations clean and neat. There must not beany eating, drinking, or use of tobacco products in thework area.

2. Minimize the handling of electronic assemblies andcomponents to prevent damage.

3 When gloves are used, they need to be changed asfrequently as necessary to prevent contamination fromdirty gloves.

4. Solderable surfaces are not to be handled with barehands or fingers. Body oils and salts reduce solderabil-ity, promote corrosion and dendritic growth. They canalso cause poor adhesion of subsequent coatings orencapsulates.

5. Do not use hand creams or lotions containing siliconesince they can cause solderability and conformal coat-ing adhesion problems..

6. Never stack electronic assemblies or physical damagemay occur. Special racks need to be provided inassembly areas for temporary storage.

7. Always assume the items are ESDS even if they are notmarked.

8. Personnel must be trained and follow appropriate ESDpractices and procedures.

9. Never transport ESDS devices unless proper packagingis applied.

IPC-7711

Number: 2.1

Revision: A

Date: 5/02


Page 3 of 4

NOTES

IPC-7711

Number: 2.1

Revision: A

Date: 5/02


Page 4 of 4

EQUIPMENT REQUIRED

Continuous vacuum desoldering systemDesoldering tipDamp sponge

OPTIONAL EQUIPMENT

N/A

MATERIALS

Flux-cored solderFluxCleanerTissue/wipes

PROCEDURE

1. Remove conformal coating (if any) and clean work area of any contamination,oxides, residues or fluxes.

2. Install thermal drive desoldering tip handpiece.

3. Start with tip temperature of approximately 315°C and change as necessary.

4. Apply flux to all solder connections (optional).

5. Thermal shock tip with damp sponge.

6. Tin tip with solder.

7. Lower tip contacting solder connection. (See Figure 1.)

8. Confirm complete solder melt of contacted lead. (See Figure 2.)

NOTEAuxiliary heating may be required on solder joints with a large thermal mass.This is most common on multilayer PC boards.

9. For a flat lead, move lead back and forth; for a round lead, use a circular motionand apply vacuum while continuing lead movement. (See Figures 3 & 4.)

10. Lift tip from lead, hold vacuum for sufficient time to clear all molten solder fromheater chamber. (See Figure 5.)

11. Repeat for all solder connections.

12. Re-tin tip end with solder and return handpiece to its stand.

13. Clean lands as required for component replacement.

Figure 1 Position Tip

Figure 2 Melt Solder

Figure 3 Move Lead & Apply Vacuum

Flat Lead

Figure 5 Lift Handpiece

Figure 4 Move Lead & Apply Vacuum

Round Lead

7711Rework of


Revision: ADate: 5/02

Through-Hole DesolderingContinuous Vacuum Method

Number: 3.1.1

Product Class: R, F, W




Page 1 of 2

NOTES

IPC-7711

Number: 3.1.1

Revision: A

Date: 5/02

Subject: Through-Hole Desoldering

Page 2 of 2

EQUIPMENT REQUIRED

Continuous vacuum desoldering systemDesoldering tipDamp sponge

OPTIONAL EQUIPMENT

N/A

MATERIALS


NOTE

On multileaded devices a skipping/alternating pattern may be needed to reduce heatbuildup.

PROCEDURE


2. Install desoldering tip handpiece.





7. Lower tip contacting solder connection.

8. Confirm complete solder melt of contacted lead and gently straighten the leadto a vertical position. (See Figure 1.)


10. Lift tip from lead, hold vacuum for sufficient time to clear all molten solder fromheater chamber. (See Figure 4.)




Figure 1

Figure 2

Flat Lead

Figure 3

Round Lead

Figure 4

7711Rework of


Revision:Date: 5/02

Through-Hole DesolderingContinuous Vacuum Method – Partial Clinch

Number: 3.1.2





Page 1 of 2

NOTES

IPC-7711

Number: 3.1.2

Revision:

Date: 5/02


Page 2 of 2

EQUIPMENT REQUIRED

Continuous vacuum desoldering systemDesoldering tipDamp spongeNon-metallic tool (wood stick or spudger)Flat nose pliers

OPTIONAL EQUIPMENT

N/A

MATERIALS


NOTES


PROCEDURE


2. Install desoldering tip handpiece.





7. Lower tip contacting solder connection.

8. Confirm complete solder melt of contacted lead and apply vacuum. (See Figure1.)

9. Lift tip from lead, hold vacuum for sufficient time to clear all molten solder fromheater chamber.

10. Inspect connection to ensure only a small amount of solder remains betweenlead and land area.

NOTE: If excess solder exists use wicking braid and iron to remove solder. (See3.1.5.)

11. Using a Flat Nose pliers gently rotate the lead laterally until the joint separates.(See Figure 2.)

Figure 1

Figure 2

Figure 3

7711Rework of


Revision:Date: 5/02

Through-Hole DesolderingContinuous Vacuum Method – Full Clinch

Number: 3.1.3





Page 1 of 2

12. Lift lead with wood stick to vertical position. (See Figure 3.)




IPC-7711

Number: 3.1.3

Revision:

Date: 5/02


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EQUIPMENT REQUIRED

Soldering IronContinuous vacuum

desoldering systemDesoldering tipChisel tip

Damp spongeNon-metallic tool (wood

stick or spudger)Flat nose pliers

OPTIONAL EQUIPMENT

N/A

MATERIALS

Flux-cored solderFlux

CleanerTissue/wipes

NOTE: On multileaded devices a skipping/alternating pattern may be needed toreduce heat buildup.

PROCEDURE


2. Install soldering iron tip and desoldering tip into handpieces.




6. Lower soldering iron tip contacting solder connection. (See Figure 1.)

7. Confirm complete solder melt of contacted lead

8. Lift lead with a non-metallic tool to the vertical position. (See Figure 2.)

9. Lower desoldering tip contacting solder connection.

10. Confirm complete solder melt of contacted lead.


12. Lift tip from lead, hold vacuum for sufficient time to clear all molten solder fromheater chamber.




Figure 1

Figure 2

Figure 3

Flat Lead

Figure 4

Round Lead

7711Rework of


Revision:Date: 5/02

Through-Hole DesolderingFull Clinch Straightening Method

Number: 3.1.4





Page 1 of 2

NOTES

IPC-7711

Number: 3.1.4

Revision:

Date: 5/02


Page 2 of 2

EQUIPMENT REQUIRED

Soldering ironChisel tipDamp spongeNon-metallic tool (wood stick or spudger)Wicking braid

OPTIONAL EQUIPMENT

N/A

MATERIALS


NOTE


CAUTION

This procedure is not recommended for the removal of solder in plated-throughholes due to the risk of conductor damage. This method should only be used whenno other method exists. Wicking is most affective on surface solder only.

CAUTION

Trim the wicking braid to prevent damage to other land areas or components.

PROCEDURE


2. Install soldering iron tip in handpiece.




6. Apply braid material to lead land junction. (See Figure 1.)

7. Lower tip contacting braid material connection.

8. Observe solder wicking into the braid material.

Figure 1

Figure 2

7711Rework of


Revision:Date: 5/02

Through-Hole DesolderingFull Clinch Wicking Method

Number: 3.1.5


Skill Level: Advanced



Page 1 of 2

NOTE: Once solder stops wicking into the braid material remove the iron andbraid material immediately.

9. Remove tip and braid material.

10. Confirm complete solder removal from area.

11. Lift lead with a non-metallic tool to the vertical position. (See Figure 2.)




IPC-7711

Number: 3.1.5

Revision:

Date: 5/02


Page 2 of 2

EQUIPMENT REQUIRED

Soldering ironChisel or conical tipDamp spongeWood stick or tweezers

MATERIALS


NOTE

Preheating is recommended for sensitive components (i.e., chip capacitors).

PROCEDURE


2. Install soldering iron tip in handpiece.


4. Apply flux to one land (optional).


6. Prefill one land with solder. (See Figure 1.)

7. Place the component in position and hold it with a wooden stick or tweezers.

8. Apply flux to both lands.

9. Place the tip at the junction between the prefilled land and termination area ofcomponent.

10. Observe complete solder melt. This is evident by component dropping downonto land. area. (See Figure 2.)

11. Pause briefly for solder to solidify

12. Solder remaining side by applying additional solder as needed. (See Figure 3.)



Figure 1

Figure 2

Figure 3

7711Rework of


Revision:Date: 5/02

Chip InstallationPoint to Point Method

Number: 5.3.2

Product Class: R, F, W, C




Page 1 of 2

NOTES

IPC-7711

Number: 5.3.2

Revision:

Date: 5/02

Subject: Chip Installation

Page 2 of 2

EQUIPMENT REQUIRED

Soldering systemFlat faced or cup-shaped tipDamp spongeVacuum pick-up tool

OPTIONAL EQUIPMENT

Tweezers

MATERIALS

Flux-cored solderFluxCleaner

PROCEDURE

1. Install selected tip into the soldering handpiece.


3. Position the component ensuring proper lead-to-land alignment. Hold the com-ponent in place using the vacuum pick-up tool or tweezers. (See Figure 1.)

4. Apply flux and tack solder opposing corner leads. (See Figure 2.)

5. Apply flux to remaining lead/land areas. (See Figure 3.)

6. Clean tip using a damp sponge.

7. Apply solder to tip to create a bead of molten solder. (See Figure 4.)

8. Position tip so the solder bead contacts the top portion of leads. Slowly movetip over the row of leads to form proper solder fillets at each joint. (See Figure5.)

9. Repeat steps 7 through 8 on remaining sides of component.

10. Re-tin tip with solder.

11. Clean, if required, and inspect.

Figure 1 Position Component

Figure 2 Tack Lead

Figure 3 Flux Leads

Figure 4 Fill Tip

Figure 5 Solder Component

7711Rework of


Revision: ADate: 5/02

Gull Wing InstallationMulti-Lead Method – Top of Lead

Number: 5.5.1

Product Class: R, F, W, C




Page 1 of 2

NOTES

IPC-7711

Number: 5.5.1

Revision: A

Date: 5/02

Subject: Gull Wing Installation

Page 2 of 2

EQUIPMENT REQUIRED

Solder removal systemConvective reflow stationReballing fixture

OPTIONAL EQUIPMENT

Reflow ovenBake-out (vacuum, convection) oven

MATERIALS

FluxCleanerTissue/wipesSolder spheres

NOTE

Moisture sensitive components (as classified by IPC/JEDEC J-STD-020 or equivalentdocumented procedure) must be handled in a manner consistent with J-STD-033 oran equivalent documented procedure.

CAUTION

Verify component can withstand the multiple reflow cycles.

PROCEDURE

1. Remove excess solder in accordance with procedures 4.1.2, 4.1.3, or 4.2.1

2. Clean and inspect BGA for coplanarity.

3. Apply flux to land on BGA. (Figure 1.)

4. Insert the BGA into the applicable reballing fixture and secure. (Figure 2.)

5. Carefully pour solder sphere into fixture. (Figure 3.)

6. Drain off all excess spheres. Ensure all holes in fixture have a solder sphere.

7. Reflow solder spheres using the established profile. (Figure 4.)

8. Allow BGA to cool and remove from fixture.

9. Clean (if necessary) and inspect the BGA.

Figure 1

Figure 2

Figure 3

Figure 4

7711Rework of


Revision:Date: 5/02

BGA Reballing Procedure

Number: 5.7.3

Product Class: R, C




Page 1 of 2

NOTES

IPC-7711

Number: 5.7.3

Revision:

Date: 5/02

Subject: BGA Reballing Procedure

Page 2 of 2

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